Poly(ester-amide) adhesive compositions have been known for some time in the art, including the use as hot melt adhesives for various substrates such as metals, wood and plastics. Included in this background of poly(ester-amide) compositions are U.S. Pat. Nos. 3,650,999, 4,343,743, and 4,485,233. Each of these three patents may include a polymeric fat acid component. U.S. Pat. No. 3,650,999, related to poly(ester-amide) compositions, is generally useful as adhesives to a variety of substrates such as steel, aluminum, wood and plastic substrates. By the proper selection of reactants and using special polymerization techniques, a block copolymer poly(ester-amide) composition was prepared having certain advantages in high temperature properties over earlier adhesive compositions. However, the products do not possess good low temperature properties. The block copolymer is a composition comprising from 30 to 70% by weight crystalline polyester segments and 70 to 30% of amorphous polyamide segments. The polyesters employed were high melting crystalline polyesters of aromatic acids and glycols and copolyesters thereof, which provided polyester segments having melting points in the range of 180.degree. to 270.degree. C.
U.S. Pat. No. 4,343,743 deals with copoly(ester-amides) having a random, alternately or regularly recurring block structure in which the improvement over U.S. Pat. No. 3,650,999 is alleged as providing products having a glass transition temperature below -30.degree. C. so that the polymers remain pliable down to temperatures of that level. However, the products do not possess good heat fail properties. As disclosed in this patent, the proportion by weight of polyester segments is preferably between 50 and 80% by weight although a general range of 20 to 80% is disclosed.
U.S. Pat. No. 4,485,233 relates to poly(ester-amide) compositions which include a polymeric fat acid component and which are indicated as employing diamines and diols which contain a high proportion of non-hydrogen bonding groups or an odd number of carbon atoms to provide advantageous crystallization properties which permit long open assembly times. Within the general requirement that substantially equivalent amounts of carboxyl and amine groups be present in the reaction mixture provide a neutral or balanced poly(ester-amide), the proportions of the reactants are 10 to 60 equivalent percent of the polymeric fatty acid, 40 to 90 equivalent percent of another dicarboxylic acid, 40 to 90 equivalent percent of a diamine and 10 to 60 equivalent percent of a diol.